title: Short communication: the beta-casein (CSN2) silent allele C1 is highly spread in goat breeds.
abstract: Several single nucleotide polymorphisms have been identified in the goat milk casein genes, most of them modifying the amino acid sequence of the coded protein. At least 9 variants have been found in goat beta-CN (CSN2); 6 of them were characterized at the DNA level (A, A1, C, E, 0, and 0'), whereas the other 3 variants were described only at the protein level. The recently identified silent A1 allele is characterized by a C-->T transition at the 180th nucleotide of the ninth exon. In the present work, typing results from different breeds (3 Italian, 3 German, and a composite of African breeds for a total of 335 samples) demonstrated that the same mutation is carried by the CSN2*C allele. In addition, the T nucleotide at the 180th nucleotide of the ninth exon was always associated with CSN2*C in all the breeds analyzed. Thus, another silent allele occurs at goat CSN2 and can be named CSN2*C1. The much wider distribution of C1 with respect to the A1 allele indicates that the single nucleotide polymorphisms characterizing the silent mutation originated from CSN2*C. A method for the identification of this allele simultaneously with 5 of the 6 DNA-characterized alleles is also proposed. The mutation involved codifies for the same protein of the C allele; nevertheless, its location in the 3' untranslated region of the gene might affect the specific casein expression.
authors.affiliation: Dipartimento di Scienze e Tecnologie Veterinarie per la Sicurezza Alimentare, Università degli Studi di Milano, Via Trentacoste 2, Milano, 20134 Italy. stefania.chessa@unimi.it
authors.forename: S
authors.initials: S
authors.lastname: Chessa
authors.forename: D
authors.initials: D
authors.lastname: Rignanese
authors.forename: J
authors.initials: J
authors.lastname: Küpper
authors.forename: G
authors.initials: G
authors.lastname: Pagnacco
authors.forename: G
authors.initials: G
authors.lastname: Erhardt
authors.forename: A
authors.initials: A
authors.lastname: Caroli
mesh_terms: D000483:Alleles; D000818:Animals; D001947:Breeding; D002364:Caseins / Q000235:genetics*; D006041:Goats / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
chemical_list: D002364:Caseins